private static Parser<Filter> query(Parser<Filter> atom) {
Parser.Reference<Filter> ref = Parser.newReference();
Parser<Filter> unit = ref.lazy().between(term("("), term(")")).or(atom);
Parser<Filter> parser =
new OperatorTable<Filter>()
.infixl(op(",", BinaryOperator.OR), 10)
.infixl(op("+", BinaryOperator.AND), 20)
.build(unit);
ref.set(parser);
return parser;
}
